The present invention generally relates to the field of force generating devices and, more particularly, force generating devices useful in orthodontic appliances, including appliances useful in developing the arch of an orthodontic patient.
Force generating devices, such as springs, elastic bands and archwires, have long been employed in orthodontics. There is a need for improved forced generating devices which provide for ease of use, ease of assembly, ease of adjustment and safety.
In accordance with the present invention, a force generating device is provided which includes an elastomeric member; a first collar for receiving a first end of the elastomeric member; a second collar for receiving a second end of the elastomeric member; an orifice, which is part of or operationally attached to the first collar, for receiving a piston; and a piston which is slidably engageable into the orifice. The piston is operationally attached to the second collar. When the force generating device is assembled, the elastomeric member operationally connects the first collar and the second collar and the piston is slidably engaged within the orifice.
The force generating member is preferably an elastomeric polymer tube having one end which frictionally engages the outer surface of the first collar and having a second end which frictionally engages the outer surface of the second collar. Preferably, the first collar and the second collar have ribbed outer surfaces in order to enhance the frictional engagement between inner surfaces of the elastomeric polymer tube and the outer ribbed surfaces of the collars. Preferably, the first collar includes a first end stop and the second collar includes a second end stop and the first end of the force generating member is limited in axial movement by the first end stop and the second end of the force generating member is limited in axial movement by the second end stop.
In one embodiment, the force generating device can be operationally interconnected with a tooth of an orthodontic patient. The device for interconnecting preferably includes a xe2x80x9ctrombone-slidexe2x80x9d shaped connector which includes means for attaching the connector to a tooth; a first segment extending at least distally from the means for attaching; a second segment interconnected with the first segment and extending at least gingivally from the first segment; and a third segment interconnected with the second segment and extending at least mesially from the second segment. The means for attaching the connector to a tooth can comprise a band attached to a tooth of an orthodontic patient, the band having a first band tube attached thereto, and a first post slidably interconnectable with the first band tube.
The force generating device can be incorporated into a variety of appliances, including appliances selected from the group consisting of lingual arch developers, labial arch developers and distallizing appliances. For example, in an arch developer the second collar is operationally attached to an arch wire.
The force generating device of the present invention can be employed as part of a connector. Preferably the connector includes as least one post which is removably insertable into a tube on a patient""s tooth (e.g, via an orthodontic band attached to the patient""s tooth). The connector also includes at least one generally horizontal or mesio-distally extending hollow tube which provides for an interface with an orthodontic appliance (e.g., the force generating device of the present invention, a lingual arch, a palatal expander, a Nance button, a bite block). When the connector interfaces with a force generating device, the hollow tube can be employed as the first collar and/or orifice. Typically, the connector will utilize two generally occlusal-gingivally extending posts (i.e., which are mesio-distally displaced) which are disposable in two generally occlusal-gingivally extending tubes (i.e., which are mesio-distally displaced) associated with a patient""s tooth.
For certain orthodontic treatment applications (e.g., mesially-directed arch expansion from the lingual or hereafter lingual arch development) it may be desirable to dispose the noted horizontal tube gingivally. One embodiment which provides a gingivally disposed horizontal tube includes a first segment which is interconnected with the post(s) and extends at least generally distally from the post (e.g., the first segment may also extend occlusally and/or gingivally). A second segment of the connector is interconnected with the first segment and extends at least generally gingivally from the first segment (e.g., the second segment may also extend mesially and/or distally, such as by being generally semicircular, i.e., such that the second segment would initially extend distally and gingivally along an arcuate path, and then mesially and gingivally along an arcuate path). Finally, a third segment of the connector is interconnected with the second segment and extends at least generally mesially from the second segment (e.g., the third segment may also extend occlusally and/or gingivally). At least the mesial-most portion of this third segment is the hollow tube. Preferably, the hollow tube is the orifice which receives the piston of the force generating device. One configuration which is encompassed by the above-described connector is a generally trombone-shaped segment inter-connected with the post(s) (either integrally or by some appropriate attachment).
The above-described embodiment may contain a variety of additional features. For instance, a fourth segment may be cantilevered from the first segment and extend mesially beyond the first post a short distance, such as to provide a handle for installing the connector (e.g., extending about 3 mm mesially beyond the mesial-most post). This fourth segment may also be curved to generally follow the surface of the adjacent tooth (e.g., the lingual). The connector may include another generally horizontally disposed or mesio-distally extending tube. One tube may be gingivally disposed as noted above, while this second horizonal tube may be more occlusally disposed. This may be affected by having this second generally horizontal tube extend mesially from the first segment of the connector.
Another feature which may be incorporated into the above-described embodiment is that the third segment may be more lingually disposed than the first segment. This may be effected by having the second segment xe2x80x9cspiralxe2x80x9d in both a gingival and lingual direction. Moreover, this may be effected by having the second segment be disposed at an angle relative to an occlusal-gingivally extending reference plane (e.g., at an angle of about 45xc2x0).
One use for the above-described force generating device and/or connector is in lingual arch development. Lingual arch development involves the application of a generally mesially-directed force on the lingual arch of an orthodontic patient. This may be affected by having a lingual arch slidably interconnected with two anchor teeth, one on each side of a patient""s mouth. It may be desirable to limit or control in some respect the mesial advancement of the lingual arch relative to these anchor teeth. The structure of the above-described embodiment may be adapted to provide this feature without adversely affecting performance of the lingual arch developer by interconnecting the force generating device of the present invention with the above-noted connector.
The above-described connector may be adapted for use in conjunction with other types of orthodontic treatments. In some cases it may be desirable to incorporate a fourth segment which is cantilevered from the first segment and extends mesially a distance whereby if this fourth segment were adapted to the lingual of a patient (e.g., bent to follow the lingual of the patient""s corresponding dentition), the free end of the fourth segment would be at least at and preferably slightly beyond the midline of the patient""s dentition. One use of this type of fourth segment is to adapt the fourth segment to the lingual of the desired dentition of the orthodontic patient. Installing a connector on each side of the patient""s mouth then results in two of these fourth segments being in an overlapping relation at generally the patient""s midline. In this configuration, one may attach the two free ends of the two fourth segments together. Various types of bends may then be placed in one or both of these fourth segments to apply desired orthodontic treatment forces to the corresponding dentition. Another option is to let the free ends of the two fourth segments act independently of each other by not joining them together such that both remain independently active. In this overlapping arrangement, it should be appreciated that the fourth segment could be bent so as to be more gingivally disposed as well if such would be desirable or required for certain applications.
Another use of the above-noted type of fourth segment when a connector is installed on each side of the patient""s mouth is to bend both fourth segments in a manner such that their respective free ends are disposed generally proximate to the forward portion of the orthodontic patient""s mouth but at a location which is away from the teeth. In this position the fourth segments may provide a frame of sorts for a frontal anchorage which does not adversely affect tooth position since the anchorage is not directly on the patient""s tooth or teeth (e.g., an acrylic may be molded over the free end portions of the two fourth segments, which acrylic will engage the patient""s soft tissue but not the patient""s teeth to provide the desired anchorage for other orthodontic treatment forces being applied to the patient). Mounting a connector on each side of the patient""s upper dentition will further allow the fourth segments to be bent to extend up to the vault of the patient""s palate. This provides a desirable mounting for certain palatal expanders.
Another aspect of the present invention relates to a lingual orthodontic assembly. A generally mesio-distally extending tube is lingually attached to a tooth on each side of the orthodontic patient""s mouth. This may be provided by installing one of the above-described connectors on each side of the patient""s mouth. As such, it should be appreciated that various aspects of the present invention may be used combinatively as well as singularly. The ends of a lingual arch are typically compressed toward each other (e.g., for arch expansion) and inserted into the associated mesio-distally extending tube such that the arch exerts an expansive (relative to the patient""s midline) force on the patient""s corresponding dentition. Two mountings (e.g., hooks) are provided on at least one side of the orthodontic assembly. One of these mountings is associated with the tooth on which one of the mesio-distally extending tubes is installed. The other may be associated with another tooth on the same side of the patient""s mouth, but is more preferably associated with the lingual arch. A torquing member is attached to and extends between each of these mountings to apply a torquing force to at least the tooth on which the mesio-distally extending tube is installed. This may be affected by wrapping the torquing member about the horizontal tube and/or the lingual arch. Appropriate torquing members include elastics (e.g., energy chain elastics). In the case where the above-described connector is used, the torquing member would be wrapped around both the third segment of the connector and then the sectional. It should be appreciated that this aspect of the invention could be incorporated on only one side of the patient""s mouth, but would preferably be used on both sides of the patient""s mouth.